Alcoholysis of beta-alkoxy methyl ethers



Patented 13, 1940 UNITED STATES ALCOHOLYSIS or fl-ALKOXY METHYL ETH PATEN oFF-ics Donald J.- Loder, William F. Gresham, and Donald B. Killian, Wilmington, Del., assignors toE. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware I No Drawing. Application February 24, 1939,

Serial No. 258,179

cmoncmoxom .CHzOI-I,

wherein X is a methylene or substituted methylene group and Y is an alkyl group, specific examples of which are glycerol beta (methoxy methyl) ether, CI-hOHCI-HOCHzOCI-h) .CI-IzOI-I; glycerol 20 beta (ethoxy methyl) ether,

, cmoncmocmoczrnmmon; glycerol beta (propoxy methyl) ether,

, crnoncmocraocsnv amen; glycerol beta (alpha. methoxy ethyl) ether,

OHaOH.CH(OOHOGHi)CHzOH 30 and the like, which compounds may be prepared" a process for the preparation of glycerol. A further object of the invention is to provide such a process wherein glycerol is obtained from betasubstituted glycerol ethers in which a hydrogen of an ether group has been replaced by an alkoxy or substituted alkoxy group. A further object of the invention is to provide a process whereby an alkoxy alkyl group of a glycerol beta (alkoxy methyl) ether is replaced by a hydrogen atom. Other objects and advantages of the invention will hereinafter appear.

Glycerol .may be made in accord with, the process of this invention by interacting a glycerol beta-(alkoin alkyl) ether having the generic formula, CI-IaOECI-IflOXOY) .CI-IzOI-I, wherein X is a methylene or substituted methylene group and Y is an alkyl group such as methyl, ethyl, propyl, butyl, isobutyl, or higher alkyl groups or an aryl group such as benzyl, tolyl, etc., by inter- 55 acting the glycerol ether with-an alcohol (preferably an alcohol, the alkyl, group of which is the same as'the Y group of the compound reacted) in the presence of inorganic acids, for example, sulfuric, phosphoric and more particularly, the halogen acids such as hydrochloric, hydrobromic, hydriodic acids, etc. stantially in accord with the reaction:

wherein R is an alkyl or aryl group.

The reaction is conducted by refluxing a mixture of the glycerol ether, alcohol andcatalyst at a temperature ranging between 40 and 120 0.,

the temperature being determined by the boiling point of the mixture and pressure above it. The alcohol should be present,'on a molal basis, preferably in excess, over the ether,. although equimolar proportions or even lower proportions may be used.- Ordinarily, the reaction proceeds satisfactorily at atmospheric pressure, although pressuresin excess of atmospheric or pressures below atmospheric may be employed, if desired.

The more detailed practice of the invention is illustrated by the following examples inwhich parts given are by weight unless otherwise stated. There are, of course, many forms of, the invention other than these specific embbdiments.

Example 1.An autoclave provided with a fractionating column was charged with 136 parts of glycerol beta (methoxy methyl) ether, 48 parts of methanol and 0.2 part of sulfuric acid. The temperature was raised to approximately 45 C. and during the operation a methylal-methanol azeotrope (containing 92% m'ethylal) was removed by iractionation continuously as formed. Heating was stopped when methanol alone distilled over, the surfuric acid was then neutralized with caustic, and the glycerol product recovered in good yield by distillation under reduced pressure. The yield of glycerol was substantially quantitative.

Example 2.-An autoclave provided with a fractionating column was charged with 40 parts ofglycerol beta (ethoxy-methyl) ether, 50 parts of 95% ethanol and 0.5 part of sulfuric acid; The temperature was raised to'approximately 75, C.

and during the operation an ethylal-ethanolwater azeotrope (containing approximately 6.9% vetliylal) was removed by fractionation continuously as formed.' Heating was stopped when ethanol alone distilled over and glycerol recovered as in Example 1.

From a consideration of the above specification, it will be appreciated that many changes may be The reaction proceeds sub-' I made therein without departing from the scope of the invention or sacrificing any of its advantages.

We claimzg 1. A process for the preparation of glycerol which comprises replacing by alcoholysls and with hydrogen the alkoxy alkyl group of a glycerol beta-(alkoxy alkyl) ether.

2. A process for the preparation of glycerol which comprises reacting an alcohol with a glycerol beta-alkoxy methyl ether having the generic formula, CH2OH.CH(OXOY).CH2OH, in which X is selected from the group consisting of methylene and substituted methylene groups and Y is an alkyl group, in the presence of a hydrolyzlng catalyst.

' 3. A process for the preparation of glycerol which comprises reacting an alcohol with glycerol beta-(methoxy methyl) ether in the presence of a hydrolyzing catalyst.

. 4. A process for the preparation of glycerol which comprises reacting an alcohol with glycerol beta-(ethoxy methyl) ether 'in the presence of a hydrolyzing catalyst.

5. A process for the preparation of glycerol which comprises reacting an alcohol with glycerol beta-(propoxy methyl) ether in the presence of a hydrolyzing catalyst.

6. A process for the preparation of glycerol which comprises reacting a glycerol beta-(all'roxy alkyl) ether with an alcohol and a hydrolyzing catalyst and thereby replacing the alkoxy alkyl group of the glycerol beta-(alkoxy alkyl) ether by hydrogen.

7. A process for the preparation of glycerol which comprises reacting a glycerol beta-(alkoxy alkyl) ether with an alcohol'and a hydrolyzing 9 8. A process for the preparation of glycerol which comprises reacting a mixture containing 2,21 rose a glycerol beta-(methoxy methyl) ether, methanol and a hydrolyzing catalyst until substantially all of the methoxy methyl group of the glycerol beta-(methoxy methyl) ether has been converted to methylal.

9. A process for the preparation of glycerol which comprises reacting a mixture containing a glycerol beta-(ethoxy methyl) ether, ethanol and a hydrolyzing catalyst until substantially all of the ethoxy methyl group of the glycerol beta (ethoxy methyl) ether has been converted to diethyl ether of methylene glycol.

10. A process for the preparation of glycerol which comprises reacting a mixture containing a glycerol beta-(propoxy methyl) ether, propanol and a hydrolyzing catalystuntil substantially all of the propoxy methyl group of the glycerol beta- (propoxy methyl) etherhas been converted to dipropyl ether of ethylene glycol.

11. A process for the preparation of glycerol which comprises reacting approximately 136 parts of glycerol beta-(methoxy methyl) ether with approximately 48 parts of methanol and 0.2 part of sulfuric acid, distilling off the methylal formed and recovering glycerol from the reaction product.

12. A process for the preparation of glycerol which comprises reacting approximately parts of glycerol beta-(ethoxy methyl) ether with approximately 50 parts of 95% ethanol in the presence of 0.5 part of sulfuric acid, conducting the reaction at approximately C. and during the reaction removing by distillation an ethylalethanol-water azeotrope, continuing the removal of the azeotrope until substantially no ethylal is contained therein and subsequently recoverin glycerol from the reaction product.

DONALD B. W. WILLIAM F. GRESHAM. DONALD J. LODER. 

